1、IEEE Std C57.146-2005IEEE Guide for the Interpretation ofGases Generated in Silicone-ImmersedTransformersI E E E3 Park Avenue New York, NY 10016-5997, USA10 March 2006IEEE Power Engineering SocietySponsored by theTransformers Committee Recognized as an IEEE Std C57.146-2005(R2011) American National
2、Standard (ANSI) IEEE Guide for the Interpretation of Gases Generated in Silicone-Immersed Transformers Sponsor Transformers Committee of the IEEE Power Engineering Society Approved 29 December 2005 Reaffirmed 16 April 2012 American National Standards Institute Approved 22 September 2005 Reaffirmed 1
3、6 June 2011 IEEE-SA Standards Board Abstract: This guide is intended to apply to silicone-immersed transformers for which the silicone fluid was the fluid supplied when the transformer was originally manufactured. It does not address transformers that have been retro-filled. The theory of combustibl
4、e gas generation in a silicone-filled transformer, recommended procedures for sampling and analysis, recommended actions based on the interpretation of results, and a bibliography of related literature are addressed in this guide. Keywords: dissolved gas analysis, silicone _ The Institute of Electri
5、cal and Electronics Engineers, Inc. 3 Park Avenue, New York, NY 10016-5997, USA Copyright 2006 by the Institute of Electrical and Electronics Engineers, Inc. All rights reserved. Published 10 March 2006. Printed in the United States of America. IEEE is a registered trademark in the U.S. Patent +1 97
6、8 750 8400. Permission to photocopy portions of any individual standard for educational classroom use can also be obtained through the Copyright Clearance Center. Introduction This introduction is not part of IEEE Std C57.146-2005, IEEE Guide for the Interpretation of Gases Generated in Silicone-Imm
7、ersed Transformers. Since its introduction in 1974, silicone dielectric fluid has become widely accepted in power and distribution transformers. As the number of in-service transformers grows and their average age increases, the need for early detection of incipient fault conditions becomes more imp
8、ortant. Experience has shown that the detection of certain gases generated in a mineral-oil-filled transformer is frequently the first available indication of an abnormal condition that, if not corrected, may eventually lead to failure. To apply this predictive capability to silicone-immersed transf
9、ormers, work has been done to understand how their gassing characteristics relate to mineral-oil-immersed transformers. In a silicone-immersed transformer, generated gases can be found dissolved in the fluid or in the gas blanket above the fluid. The detection of an abnormal condition requires an ev
10、aluation of the amounts and types of generated gas present and the continuing rate of generation. Some indication of the source of the gases and whether solid insulation is involved may be gained by determining the identity of the generated gases. This guide was originally started in June of 1995 as
11、 IEEE P1258, Trial Use Guide for the Interpretation of Gases Generated in Silicone-Immersed Transformers. It was never published. This present version contains essentially all the same descriptions and procedures as the original version, with minor editing in order to comply with the latest IEEE sty
12、le. Notice to users Errata Errata, if any, for this and all other standards can be accessed at the following URL: http:/ standards.ieee.org/reading/ieee/updates/errata/index.html. Users are encouraged to check this URL for errata periodically. Interpretations Current interpretations can be accessed
13、at the following URL: http:/standards.ieee.org/reading/ieee/interp/ index.html. PatentsAttention is called to the possibility that implementation of this standard may require use of subject matter covered by patent rights. By publication of this standard, no position is taken with respect to the exi
14、stence or validity of any patent rights in connection therewith. The IEEE shall not be responsible for identifying patents or patent applications for which a license may be required to implement an IEEE standard or for conducting inquiries into the legal validity or scope of those patents that are b
15、rought to its attention. iv Copyright 2006 IEEE. All rights reserved. Participants At the time this guide was completed, the Guide for the Generation of Gases in Silicone-Immersed Transformers Working Group had the following membership: William H. Bartley, Chair James L. Goudie, Vice Chair Paul J. G
16、riffin Frank J. Gryszkiewicz Ted J. Haupert Frank W. Heinrichs Fredi Jakob Eugene Kallaur Joseph J. Kelly Henry A. Pearce Thomas O. Rouse Leo J. SavioThe following members of the balloting committee voted on this guide. Balloters may have voted for approval, disapproval, or abstention. David Aho Ste
17、phen Antosz Ron Barker David Barnard William H. Bartley W. J. Bergman Wallace Binder Gene Blackburn Donald Cash Juan Castellanos Tommy Cooper John Crouse R. Daubert Eric Davis Matthew Davis Guru Dutt Dhingra Jerome DiSciullo Dieter Dohnal Gary Engmann Jorge Fernandez-Daher Rabiz Foda Bruce Forsyth D
18、udley Galloway Ron Greenthaler Randall Groves Frank J. Gryszkiewicz Bal Gupta N. Kent Haggerty Wayne Hansen Ken Hanus Michael Horning James D. Huddleston, III Joseph J. Kelly Saumen Kundu Stephen R. Lambert Boyd Leuenberger Stanley Lindgren Maurice Linker Thomas Lundquist Gregory Luri Richard Marek
19、John Matthews Gary Michel Dan Mulkey Wes Patterson Jesse Patton Dan Perco Paul Pillitteri Alvaro Portillo Jeff Ray Johannes Rickmann Dinesh Sankarakurup Devki Sharma H. Jin Sim James E. Smith Brian Sparling Juan Luis Thierry Joseph Vaschak Tom Wandeloski Joe Watson James Wilson Bill Wimmer v Copyrig
20、ht 2006 IEEE. All rights reserved. When the IEEE-SA Standards Board approved this guide on 22 September 2005, it had the following membership: Steve M. Mills, Chair Richard H. Hulett, Vice Chair Don Wright, Past Chair Judith Gorman, Secretary Mark D. Bowman Dennis B. Brophy Joseph Bruder Richard Cox
21、 Bob Davis Julian Forster* Joanna N. Guenin Mark S. Halpin Raymond Hapeman William B. Hopf Lowell G. Johnson Herman Koch Joseph L. Koepfinger* David J. Law Daleep C. Mohla Paul Nikolich T. W. Olsen Glenn Parsons Ronald C. Petersen Gary S. Robinson Frank Stone Malcolm V. Thaden Richard L. Townsend Jo
22、e D. Watson Howard L. Wolfman *Member Emeritus Also included are the following nonvoting IEEE-SA Standards Board liaisons: Satish K. Aggarwal, NRC Representative Richard DeBlasio, DOE Representative Alan H. Cookson, NIST Representative Don Messina IEEE Standards Project Editor vi Copyright 2006 IEEE
23、. All rights reserved. Contents 1. Overview 1 1.1 Scope . 1 1.2 Purpose 1 2. Normative references 1 3. Definitions, acronyms, and abbreviations 2 3.1 Definitions . 2 3.2 Acronyms and abbreviations . 2 4. General theory 2 4.1 General 2 4.2 Causes of gas formation. 3 4.3 Application to equipment 4 4.4
24、 Establishing baseline data 4 4.5 Recognition of a gassing problem . 4 5. Procedures for obtaining samples of silicone liquid from the transformer and for laboratory analysis . 4 5.1 Sampling of silicone liquid 4 5.2 Determination of total dissolved gas . 5 5.3 Determination of individual dissolved
25、gases . 5 6. Suggested operating procedures utilizing the detection and analysis of combustible gases. 5 6.1 General 5 6.2 Evaluation of transformer condition using individual and TDCG concentrations. 5 6.3 Determining the operating procedure and sampling interval from the TDCG levels 7 6.4 Evaluati
26、on of possible fault type by the key gas method.7 Annex A (informative) Gas solubility 8 Annex B (informative) Key gas sourcesbased on averages from small- and large-scale experiments. 9 B.1 Thermal fluid 9 B.2 Thermal cellulose 9 B.3 Electrical partial discharge 9 B.4 Electrical arcing 11 Annex C (
27、informative) Example 12 Annex D (informative) Bibliography . 13 vii Copyright 2006 IEEE. All rights reserved. IEEE Guide for the Interpretation of Gases Generated in Silicone-Immersed Transformers 1. 1.11.22. Overview Scope This guide is intended to apply to silicone-immersed transformers in which t
28、he silicone fluid was the fluid supplied when the transformer was originally manufactured. This guide also addresses the following: The theory of combustible gas generation in a silicone-filled transformer Recommended procedures for sampling and analysis Recommended actions based on the interpretati
29、on of results A bibliography of related literature Purpose The purpose of this guide is to assist the transformer operator in evaluating dissolved gas analysis (DGA) data obtained for silicone-filled transformers. Other techniques such as fixed instruments and gas space analysis may well have utilit
30、y for silicone-filled units; however, due to a lack of data at this time, this guide will focus only on DGA. Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, t
31、he latest edition of the referenced document (including any amendments or corrigenda) applies. ASTM D 2945, Standard Test Method for Gas Content of Insulating Oils.1ASTM D 3487, Standard Specification for Mineral Insulating Oil Used in Electrical Apparatus. 1ASTM publications are available from the
32、American Society for Testing and Materials, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, USA (http:/www.astm.org/). 1 Copyright 2006 IEEE. All rights reserved. IEEE Std C57.146-2005 IEEE Guide for the Interpretation of Gases Generated in Silicone-Immersed Transformers ASTM D 3612, Standa
33、rd Test Method for Analysis of Gases Dissolved in Electrical Insulating Oil by Gas Chromatography. ASTM D 3613, Standard Practice for Sampling Insulating Liquids for Gas Analysis and Determination of Water Content. ASTM D 4652, Standard Specification for Silicone Fluid Used for Electrical Insulation
34、. 3. 3.13.24.4.1Definitions, acronyms, and abbreviations For the purposes of this guide, the following terms and definitions apply. The Authoritative Dictionary of IEEE Standards Terms B12should be referenced for terms not defined in this clause. Definitions 3.1.1 dissolved gas analysis (DGA): The e
35、xtraction, detection, and quantification of gases dissolved in insulating fluid. 3.1.2 total combustible gas (TCG): The sum (in percent) of all combustible gases including carbon monoxide and excluding oxygen reported as a percent of the transformer gas space. 3.1.3 total dissolved combustible gas (
36、TDCG): The sum of all combustible gases that are dissolved in the insulating fluid. Acronyms and abbreviations DGA dissolved gas analysis TCG total combustible gas TDCG total dissolved combustible gas General theory General Silicone fluids used in transformers are polydimethylsiloxane fluids, which
37、are considerably different in composition than transformer mineral oils. Figure 1 shows a typical chemical structure. Although many of the gases generated under thermal and electrical stress are the same for mineral oils and silicone fluids, there are differences in proportions of these gases. As in
38、dicated in Table A.1, some gases have a different solubility in silicone fluid than in mineral oil. Annex B shows typical gas concentrations for the various conditions, which can generate fault gases in silicone-immersed transformers. Thus, different concentrations of those gases would be expected i
39、n the silicone fluid than in mineral oil. 2The numbers in brackets correspond to those of the bibliography in Annex D. 2 Copyright 2006 IEEE. All rights reserved. IEEE Std C57.146-2005 IEEE Guide for the Interpretation of Gases Generated in Silicone-Immersed Transformers Figure 14.24.2.14.2.24.2.34.
40、2.4Chemical structure of silicone transformer fluid (50cS), polydimethylsiloxane Causes of gas formation The two principal causes of gas formation within an operating transformer are thermal and electrical stresses. Abnormally high conductor temperatures produce gases from thermal decomposition of t
41、he silicone fluid and solid insulation. Gases are also produced from decomposition of the silicone fluid and solid insulation exposed to partial discharge activity and the high temperatures associated with an electrical arc. Fluid thermal decomposition Overheating of silicone fluid results in partia
42、l degradation of the fluid and generation of low molecular weight gases. Gas composition is dependent on the dissolved oxygen content in the silicone fluid, the proximity of bare copper, and temperature. As the concentration of dissolved oxygen increases, methane (CH4) production decreases and small
43、 amounts of hydrogen (H2), carbon monoxide (CO), and ethylene (C2H4) are also generated. If the silicone fluid contains a high concentration of dissolved oxygen, large volumes of both carbon monoxide and carbon dioxide (CO2) will be generated. Minor components include methane and ethylene. In-servic
44、e silicone fluid typically contains dissolved oxygen. Even though dissolved oxygen is present, overheating of silicone fluids in the presence of bare copper results in the production of predominantly methane. Cellulosic thermal decomposition Overheating of cellulosic insulation in a silicone-immerse
45、d transformer will result in the production of both carbon monoxide and carbon dioxide. The ratio of carbon monoxide to carbon dioxide is temperature dependent. Hydrocarbon gases are not usually generated in significant quantities from the cellulosic insulation alone, and therefore the absence of th
46、ese gases may help distinguish between overheating of the silicone fluid and overheating of the cellulosic insulation. Cellulose degradation products such as 2-furfuraldehyde and other furan derivatives, which are soluble in the silicone fluid, may provide useful information about cellulose decompos
47、ition. This analysis can determine when solid or fluid insulation, or both, have been subject to overheating. Partial discharge decomposition Hydrogen and methane are the predominant gases generated by partial discharges in a silicone-immersed transformer. Small amounts of carbon monoxide, acetylene
48、, and ethane may also be generated. Electrical arcing decomposition The major gases generated during arcing in a silicone-immersed transformer are hydrogen, methane, carbon monoxide, and low levels of acetylene. The gases generated from the silicone fluid contain a much greater ratio of hydrogen to
49、acetylene in comparison to the gases generated from a mineral-oil-filled transformer. The presence of any amount of acetylene in a silicone-immersed transformer may be an indication of a potentially serious problem. 3 Copyright 2006 IEEE. All rights reserved. IEEE Std C57.146-2005 IEEE Guide for the Interpretation of Gases Generated in Silicone-Immersed Transformers 4.34.44.55.5.1Application to equipment All silicone-immersed transformers generate gases to some extent at normal operating temperatures. Occasionally, a gas generating abnor
